[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH] x86/efi: Reserve EFI properties table



On 05/15/2017 02:52 PM, Julien Grall wrote:
Hi Andrew,

On 08/05/17 17:29, Andrew Cooper wrote:
On 08/05/17 17:17, Ross Lagerwall wrote:
Some EFI firmware implementations may place the EFI properties table in
RAM marked as BootServicesData, which Xen does not consider as reserved.
When dom0 tries to access the EFI properties table (which Linux >= 4.4
does), it crashes with a page fault.

The pagefault is just a side effect of Linux blindly assuming that the
ioremap() request succeeded.

From Xen's point of view, Dom0 tries to map a page which doesn't belong
to dom_xen, resulting a permission failure.

  Fix this by unconditionally
marking the EFI properties table as reserved in the E820, much like is
done with the dmi regions.

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

This is probably also 4.9 material.

It looks like Jan had some comments on this patch. I haven't seen any
reply from Ross, I will wait before looking from a release perspective.


Jan had some comments on that patch but essentially NAKed it on
principle so I don't think it will be going into 4.9.

Thanks,
--
Ross Lagerwall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.